Woodwind musical instruments, e.g., saxophones and clarinets, and other devices such as bird calls, utilize the vibration of a reed in response to a flow of air to generate a tone. These reeds include natural cane reeds and synthetic reeds. Tone generation in general depends on proper reed vibration. The reed is typically placed in contact with a mouthpiece to cover an opening or window. The reed is held in place by an adjustable clamp or ligature that surrounds the mouthpiece and the reed. Variations in the mouthpiece and ligature affect the vibration of the reed and, therefore, the performance or tone of the device or instrument.
An essential function of the mouthpiece of a woodwind instrument is to provide support for the reed over an aperture that allows the reed to vibrate and to direct the energy from reed vibration through the aperture and into the bore of the instrument. The function and performance of a mouthpiece is influenced by the arrangement and geometry of the facing around the aperture as well as tone chamber below the reed, which defines the route from the aperture to the bore. The facing is conventionally a flat surface on the mouthpiece surrounding the aperture, and the reed is placed in contact with this flat surface, covering the aperture. The facing includes the aperture, called a window, and the window is surrounded by a table on one end, two side rails extending from the table and a tip rail opposite the table. The reed functions as a reed valve during vibration, opening and closing the window.
In conventional mouthpieces, the reed is affixed tightly against the flat portion of the facing to secure the mounting of the reed and to affect an airtight seal of the reed with the mouthpiece. In addition, the top surfaces of the side rails that are in contact with the reed are flat. The tone chamber is conventionally formed as a rectangular box having straight interior walls and a flat generally rectangular bottom surface. The transitions from the top surfaces to the interior walls and from the interior walls to the bottom surface are right angles.
In a conventional single-reed mouthpiece, the surface geometry of the mouthpiece at the inlet of the aperture between the reed and the mouthpiece rails is not conducive to enabling an efficient flow of air through the aperture during the negative-pressure portion of the oscillatory cycle. This restriction of airflow effects a damping of the oscillation, thereby reducing the resonance (Q) of the system. The effect on performance is to reduce the accuracy of intonation, tonal quality, and playability.